# A153965 (b-file synthesized from sequence entry)
0 1
1 2
2 2
3 4
4 15
5 31
6 126
7 927
8 3933
9 31429
10 472959
11 4005742
12 63878219
13 1917687587
14 32433255622
15 1032580394091
16 61890749905798
17 2090664356692297
18 132950076813594995
19 15915454829832076325
20 1073793991171675728498